Process and apparatus for removing oxygen from steam



Nov. 17, 1931. A. B. LAMB 7 1,832,401

PROCESS AND APPARATUS FOR REMOVING OXYGEN FROM STEAM Filed Aug. 5, 1925 dbbouww Patented Nov. 17, 1931 UNITED STATES OFFICE ARTHUR B. LAMB, OF CAMBRIDGE, MASSACHUSETTS.

Application filed August 5, 1925. Serial No. 48,365.

This invention relates to a method and apparatus for removing gaseous oxygen from steam.

The internal corrosion of steel and iron piping systems containing steam is an important and serious economic waste. Nhile itmay be greatly hastened by other causes, it depends directly or indirectly upon the gaseous oxygen contained in the steam. The amount of this oxygen may be decreased by the use of de-aerators, etc, in the feed water system, but this entails considerable expense, and the ole-aeration usually is not complete. Moreover, when the steam is electrically produced, oxygen is, in general, introduced into the steam in the boiler in a greater or less amount.

Among the objects of this invention is the production of steam which is oxygen-free, or substantially so, for use in chemical processes where steam of such quality is desired.

Other further and more specific objects of this invention will become readily apparent to persons skilled in the art from a consideration of the following description when taken in conjunction with the accompanying drawing.

The apparatus shown in the drawing comprises a vessel (1) containing granular fragments, turnings, shavings, sheets or pieces of anoxidizable material (2), for example metallic iron or a lower oxide of-iron, to the action of which the steam is subjected. In order to obtain a higher temperature, when desired, the vessel may be wound with a heating element through which a suitable electric current may be sent. The vessel (1) is preferably surrounded by an insulating jacket (4), which serves to assure an even distribution of temperature and effects economy of heat. The incoming steam enters through the valve (5) and pipe (6) and is preferably made to pass downward between the vessel (1) and insulating jacket (4:), and enters the vessel (1) containing the treating material (2) through the perforated bottom (7) and passes upward through the mass of treating material (2) and after treatment out through the pipe (8) and valve (9). By conducting the incoming steam through the considerable elevation of the temperature of the active treating material (3) without an equal increase in the temperature of the issuing treated steam.

The steam may be supplied from any suitable generator, and in the specific illustra- 6 tion of the drawing an electric boiler (10) is shown connected by means of the conduit or pipe (11) to the valve (5) of the steam deoxidizing vessel (1). The electrodes (12) and (13) are suitably insulated from the boiler.

The active treating material may be varied, depending on the pressure at which the steam boiler operates, the required purity of the steam, the superheat desired or permissible, and on other particular factors. For steam at 125 pounds pressure, the lower oxide of iron is efiective without the application of additional heat particularly, if this material is prepared by first reducing granular magnetite to active iron, and then treating this with steam until substantially no further oxidation of the active iron by'the steam itself takes place. For higher pressures of steam, and hence for higher temperatures, a less active variety of iron may be used, or metals, such as copper which are not attacked by steam. For lower pressures of steam, heat may be applied to the active material as indicated above, in order to insure a sufiiciently rapid combination with the gaseous oxygen. The active material which I employ, for example the active iron prepared as described above, is a more easily oxidizable material than the vessel containing same and the material forming the inner lining of the steam generator or boiler.

In some cases, especially where steam is generated by electric heating, the steam will carry not only oxygen, but also hydrogen, and frequently the quantity of this hydrogen is twice or several times as great as that of the oxygen. In such cases, certain of the above materials act in a catalytic tashion; that is, they cause the removal of all or part of the oxygen by combination with gaseous hydrogen in the steam, and thus entail no consumption of active material. This, for instance, is the case with the iron oxide n'epared as above, and also with the similar oxide of nickel. Whether the action is a physical one, or whether the oxygen first combines with the active material to form an oxide of t 1e metal, or a higher oxide from the original oxide, which oxygen is then removed by the hydrogen, cannot be stated, but the net effect the removal of the oxygen and a corresponding amount of the hydrogen without permancnt consumption of the active material.

In cases where a considerable quantity oi. hydrogen occurs along with the oxygen pres ent in the steam, instead of using the iron for relieving the steam of the oxygen, hopcalite or other oxidizing catalysts may be used. The preparation of these catalysts is described in U. S. Patent No. 1.345.323 to Jose h C. Vi. Frazer and Charles C. Scalic-M The hopcalite operates at a much lower temperature than the iron and it used instead of the iron it would not be necessary to heat same to as high a temperature.

In the claims, the expression metallic is intended to cover not only the pure meta itself but also compounds of the metal, such as oxides.

Although my process and apparatus for removing the oxygen from steam is especially Valuable in the treatment of steam generated in electric boilers by the passage of an electric current into a body of water serving as the electrolyte, my invention is not limited thereto, at can be employed to advantage also in the treatment of steam generated in other types of boilers, for example an ordinary fuel-burning boiler.

The present invention is not limited to the specific details set forth in the foreg Ing examples which should be construed illustrative and not by way of limitation, and in View of the numerous modifications which may be effected therein without departing from the spirit and scope of this invention it is desired that only such limitations be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a. process of producing oxygen-free steam, generating slcam by passing an electric current into a body of water serving as the electrolyte and then treating the gaseous evolved steam with a heated metallic substance which forms with oxygen a compound substantially stable at the teniperatiu'e of the heated metal, and is more easily oxidized than the material of the steam generator, but not appreciably acted upon by the steam.

2. In a process of producing oxygen-free steam, generating steam by passing an electric current into a body of water serving as the electrolyte and then passing the gaseous evolved steam through a mass of heated granules of a. metal which catalyzes the 'eaction between hydrogen and oxygen to form water, said catalytic metal forming with oxygen a substantially stable compound and being more easily oxidized than the material of the container, but not aypreciably acted upon by the steam.

3. In combination, an electric steam generator having means for passing an electric current into a body of water, a vessel. containing a body of n'ietallic grani'iles iorn'ling a substantiall stable compound with oxygen and. being more easily oxidized than the material of the steam generator, but not being appreciably acted upon by the steam, a c0nduit connecting the interior of said vessel with the interior of said steam generator and means for heating the metallic granules within sai d vessel.

l. In combination, an electric steam gcncram]: having means for passing an electric current into a. body of. water, a vessel containing granules of" iron forming a substantially stable compound 'ith oxygen and being more easily oxidized than the material of the steam generator, but not being appreciably acted upon by the steam, a conduit connecting the .inte im off said vessel. with the interior oi. said steam generator and means for heating the iron granules within said vessel.

In combination, an electric steam generator having means for passing an electric current into a body of water, a vessel containing granules of a metallic catal st which accelerates the reaction between oxygen and hydrogen to form water, a conduit for the passage of steam from said steam generator into said vessel and means for heating said catalyst, said metallic catalyst forming with oxygen a substantially stable compound and being more easily oxidized than the material of the container, but not appreciably acte 1 upon by the steam.

6. In a process of removing gaseous oxygen from steam, bringing all of the steam in thorough and. intimate contact with a substance of large specific surface selected from the group consisting of iron, nickel, copper, the oxides of these metals and hopcalite and forming a stable compound of the said substance with the oxygen while acting upon the steam per se to no significant extent.

n1 a process of removinggaseous oxygen 'lrom steam, bringing all of the steam in thorough and intimate contact with a heated substance of large specific surface selected from the group consisting of iron, nichcl, copger, the oxides of lb. 0 metals and hopcalite and forming a stable compound of the said substance with the oxygen while acting upon the steam per se to no significant extent.

8. In a process of removing gaseous oxygen from steam, bringing all of the steam in thorough and intimate contact with a substance of large specific surface selected from the group consisting of iron, nickel, copper and the oxides of these metals and forming a stable compound of the said substance with the oxygen while acting upon the. steam per se to no significant extent.

9. In a process of removing gaseous oxygen from steam containing both gaseous oxygen and hydrogen, bringing all of the steam in thorough and intimate contact with a substance of large specific surface selected from the group consisting of iron, nickel, copper, the oxides of these metals and hopcalite and forming a stable compound of said substance with the oxygen while acting upon the steam per se to no significant extent and effecting catalytic reaction between some of the hydrogen and oxygen.

10. In a process of removing gaseous oxygen from steam, treating with steam a substance of large specific surface selected from the group consisting of iron, nickel, copper, the oxides of these metals and hopcalite until the steam per se has no further significant action thereon, then bringing all of the steam from which gaseous oxygen is to be removed into thorough and intimate contact with said substance and forming a stable compound of said substance with the oxygen. 7 11. In a process of removing gaseous oxygen from steam, treating with steam a substance of large specific surface selected from the group consisting of iron and the oxides of iron until the steam per se has no further significant action thereon, then bringing all of the steam from which gaseous oxygen is to be removed into thorough and intimate con tact with said substance and forming a stable compound of said substance with the oxygen. In testimony whereof I aflix my signature.

ARTHUR B. LAMB. 

